"Shoot Zhuyuan? I've heard of it..."Zhu Youzhen smiled awkwardly. In his previous life, he liked to visit military forums such as iron and blood, strong countries, etc., but insiders watched the doorway, and laymen watched the excitement, and pseudo-military fans like him who didn't know anything about weapons and equipment basically took a detour to this kind of professional terminology.

Sun Yuanhua patiently explained to him: "Most of the enemy shelling is far away. The range of the shell is limited, and in order to accurately hit, it is necessary to accurately measure the distance of the target, and then calculate and calibrate the direction, angle and amount of ammunition of the gun. If the wind speed is high, the wind factor should also be considered. This is the so-called 'shooting element'. ”

Although Zhu Youzhen understood a general idea, he saw that the artillery in front of him, whether it was the Hongyi cannon or the Franc machine gun, was simply equipped with a light door and a front sight, and there was not even a sight, so he couldn't help frowning, thinking that if nothing else, it was already difficult to be accurate just by measuring the range.

Sure enough, Sun Yuanhua said: "I heard from my mentor Father John Tang that the artillery of the Western army has begun to use telescopes to measure distances, and the error is extremely small, even within a few feet. However, the telescopes sold by the Francophone were extremely expensive, and one of them cost thousands of taels of silver, and the military department was not willing to purchase them. Therefore, we can only use visual ranging to approximate the distance of the target. ”

Next, he began to explain the visual ranging method to Zhu Youzhen and others. This is done by facing the target, extending your right arm forward and placing your right thumb between your eyes. Close your left eye and aim your right eye at the target with the left side of your thumb. Then close your right eye and open your left eye, look at the left side of your thumb with your left eye, and mentally estimate the distance between the two thumbs. Then multiply this distance by a factor of ten to get the approximate distance of the target.

Although Man Gui, Zhao Shujiao and others are the main generals in the army, they have never cared about how to fire artillery; Even Yuan Chonghuan was confused. Li Chongyao shouted even more inexplicably: "Why is this? Obviously, I want to measure the distance between me and the target, and this distance is vertical. You estimate a horizontal distance, what does the two have to do with that? ”

Zhu Youzhen gestured for a while, but suddenly realized: "I understand, isn't this equivalent to two similar triangles!" ”

Li Chongyao didn't believe that Zhu Youzhen could understand at all, and said with disdain: "Lord Wang, don't you don't know how to pretend to understand!" What triangles, four-cornered, five-pointed stars, this is a war, not a child's game! Still 'lovesick', I don't know who you are lovesick with? ”

Zhu Youzhen couldn't cry or laugh, so he had to teach the eldest lady a lesson patiently: "It's not 'lovesickness', it's similar!" Come and see! ”

He was afraid that he would not understand what he was clumsy, so he simply stood behind Li Chongyao, raised her right arm and said, "Now your two eyes and this thumb form a triangle." And the target position observed with both eyes, and your thumb, form a triangle. The two sides of these two triangles coincide, the angles are equal, and the base edges are parallel, so they are similar triangles..."

Zhu Youzhen only cared about explaining, but he forgot that the two of them were in this posture now, and it seemed that he was hugging Li Chongyao from behind. Especially this product is still holding Li Chongyao's jade hand, which is really a little ambiguous in front of everyone's eyes.

Li Chongyao was immediately embarrassed, and suddenly broke free from Zhu Youzhen's arms and said: "Just say it, what are you doing pulling and pulling?" ”

Everyone didn't notice it, and Zhu Youzhen also blushed and said, "Aren't I afraid that you won't understand?" Well, the corresponding sides of a similar triangle are proportional, and now the distance between your eyes and the length of your arms is about one to ten. Therefore, the distance between the two thumb positions and the distance between the target should also be one to ten. Do you understand that? ”

"I don't understand!" Li Chongyao said angrily, "I understand that the prince is not well-intentioned!" ”

While everyone was laughing, Sun Yuanhua said in surprise: "Your Highness, have you ever seen the translation of "Geometric Original" by your teacher Xu Guangqi? ”

"Not really." Zhu Youzhen replied honestly, thinking that he hadn't even read all the geometry textbooks in high school, let alone this kind of ancient mathematical work, and I was afraid that he wouldn't even be able to recognize a few words.

"Then you must have read Euclid's original book!" Sun Yuanhua was shocked and said, "The words triangle, similarity, and proportion are all the names pioneered by the master in the "Geometric Original", but unexpectedly they are the same as His Royal Highness!" It took ten years of effort for the teacher to translate this book, and His Royal Highness is young and can be proficient in this way, what a genius! Wechen admires His Royal Highness so much that he throws himself to the ground, please accept Wechen's worship! ”

Saying that, Sun Yuanhua was about to pick up his clothes and kneel. Zhu Youzhen hurriedly hugged him, and said with a red face: "Master Sun praised it falsely, in fact, my geometry attainments are average..."

If this junior high school math teacher could hear his boasting, he would have to fly over from another parallel world and strangle him to death!

At this time, hundreds of infantry troops rushed out of the Houjin army and launched an attack on Ning Yuan. Sun Yuanhua knew that the enemy army was just testing it, so he smiled at Zhu Youzhen and said: "Your Highness, the enemy army is here, just to test the cannon for you!" ”

He then began to explain in detail how to adjust the direction, angle and charge of the gun according to the distance of the target. In particular, the elevation angle and charge of the muzzle, because the trajectory of the shell's flight is a parabola, it is necessary to go through complex calculations to obtain the values of the elevation angle and the charge.

And there were also gunners in the Ming army defending the city, and at this time they felt that the mouth was suddenly opened. In the past, they just poured all the gunpowder from the entire powder box into the barrel at once, and the shells counted wherever they hit. After listening to Sun Yuanhua's explanation this time, I realized that there is still such a big knowledge here.

In particular, many of these people are illiterate, and they usually can't even do addition, subtraction, multiplication and division. Algebraic operations like parabola, which involve binary quadratic equations, are not understood at all, and I am so anxious that I sweat profusely.

However, Zhu Youzhen is still highly educated, although he usually doesn't need it, and he has almost forgotten it, after all, he still understands the truth and the foundation is still there. He listened carefully to Sun Yuanhua's narration, and said distressedly: "But the enemy army is a moving target, and when the ammunition is filled and fired, the people will no longer be there, even if they aim accurately, what's the use?" ”

Sun Yuanhua smiled and said, "Your Highness, you are already close to a sharpshooter!" Here's the most crucial part: anticipating the enemy's path! ”

"Oh! I understand! "Zhu Youjian is thorough at one point," that is, he must choose a good point on the enemy's advance route and aim it with artillery first. When the enemy army is about to reach this point, let's light the fire in advance. The time it takes for the fuse to burn should coincide with the time when the enemy arrives at this point. This made it possible to accurately throw shells on the enemy's head! Isn't that the amount of advance? ”

Sun Yuanhua's eyes shone with joy, and he praised loudly: "Your Highness is a true god!" Advance amount, this word is really incisive! ”

"What's so 'incisive', Master Sun, I think you're about to become the prince's 'fart'!" Li Chongyao muttered in a low voice.

There was another burst of laughter at the head of the city, and Sun Yuanhua also smiled: "It's not that Wechen blindly flatters, I think that when the teacher taught Wechen these knowledge, it took Wechen three months to digest it all!" ”

Li Chongyao said unconvincedly: "He can only talk on paper!" If you really want to open fire, it may not be good! ”

Zhu Youzhen also smiled: "Miss, don't be unconvinced!" I'm going to give you a shot to show you what it means to 'practice is the only criterion for testing truth'! ”

"'Practice is the only criterion for testing truth'?" Although Man Gui and other generals didn't feel anything, Yuan Chonghuan and Sun Yuanhua and others were all people who read poetry and books, and when they heard Zhu Youzhen's words, they suddenly felt full of philosophy. Yuan Chonghuan pondered for a long time before saying: "Your Highness's words seem to be similar to the 'knowledge of things' in "University". ”

Only then did Zhu Youzhen realize that he had spoken again. I thought that this sentence sparked a great debate about the "standard of truth" hundreds of years later, and its connotation was far more profound than the Confucian "knowledge of things" could cover. If you want to talk about it in detail, you will be completely exposed, and you hurriedly interrupted: "Everyone dodge, watch this king fire!" ”

Everyone hurriedly dodged their positions, and Zhu Youzhen saw that the enemy army was far away and the Franc cannon could not hit, so he selected a Hongyi cannon, and according to the method taught by Sun Yuanhua, he chose a point on the route that a relatively dense group of enemy troops would pass, and used this point as the benchmark to calibrate the artillery.

It's easy to say, but it's not easy to do. The Hongyi cannon weighed a thousand catties, and although it was equipped with wheels to rotate, it was still very difficult to push. Zhu Youzhen used all his strength to eat, but the cannon body still didn't move.

"Look, I knew you couldn't!" Although Li Chongyao was sarcastic, he still rushed forward to help Zhu Youzhen push the cannon, and then adjusted the cannon body to the appropriate position and angle.

While loading ammunition, Zhu Youzhen said gratefully: "Thank you for your help, the military merit medal has half of mine and half of yours!" ”

"Don't be serious, the enemy is rushing over!" Li Chongyao stomped his feet and shouted.

Zhu Youzhen immediately calmed down and carefully estimated the speed of the enemy's march. When he felt about the same, he decisively lit the fuse, blocked his ears and hurried back, while silently reciting in his heart, "The cannon of the world, the first level of preparation; Human cannon, secondary preparation; Cannons on Earth, fire! ”

When the word "launch" was pronounced, the flames on the fuse finally crept into the chamber of the gun. Hearing an earth-shattering loud bang, the Hongyi cannon erupted wildly, hitting a ten-pound iron cannonball far into the sky.

Even if this freight is good, the estimated distance and time are not the same. Those traitor troops just walked to the point where the Hongyi cannon was aimed, and the big iron ball came to the initiation. Just listen to the sound of "popping" and "clicking" endlessly, and anyone who is hit by the iron ball will all have broken bones and rotten tendons, turning into meat puree!

These people were originally used as cannon fodder, and when they saw that their companions had really become cannon fodder, they were all shocked, and they turned around and ran.

A burst of enthusiastic cheers erupted from the head of Ningyuan City: "His Royal Highness King Xin is a thousand years old, a thousand years old!" ”

Zhu Youzhen also raised his arms excitedly and shouted: "The human cannon has been successfully launched!" ”

"What 'human cannon'? It's obviously a Hongyi cannon! Li Chongyao pouted.

Yuan Chonghuan laughed and said: "Your Highness showed his might, retreated from the enemy with one cannon, and gave the name of this cannon." From now on, this cannon will be called the 'human cannon'! ”